April 21, 2011 -- People are banned by law from smoking in bars, restaurants, and work sites in half of all states in the U.S., but more action is needed to reduce heart disease and lung cancer caused by secondhand smoke, the CDC says in a new report.

Seven states have no statewide smoking restrictions at all for private work sites, restaurants, or bars, according to the CDC's Morbidity and Mortality Weekly Report.

The states are:

Indiana

Kentucky

Mississippi

South Carolina

Texas

West Virginia

Wyoming

Restaurants, bars, and private sector work sites are major places where people are subjected to secondhand smoke, the report states.

In the past 10 years, 25 states plus Washington, D.C., have enacted comprehensive smoke-free laws restricting smoking in all indoor areas of private sector work sites, restaurants, and bars.

"Eliminating smoking from worksites, restaurants and bars is a low-cost, high-impact strategy that will protect non-smokers and allow them to live healthier, longer, more productive lives, while lowering health care costs associated with second-hand smoke," CDC Director Thomas R. Frieden, MD, MPH, says in a news release. "While there has been a lot of progress over the past decade, far too many Americans continue to be exposed to secondhand smoke at their workplaces, increasing their risk of cancer and heart attacks."

Secondhand Linked to Heart Disease, Cancer

"Completely prohibiting smoking in all public places and workplaces is the only way to fully protect non-smokers from second-hand smoke exposure," she says in the CDC news release.

Even though many states and local areas have passed smoke-free laws and ordinances, about 88 million nonsmoking Americans age 3 or older are still exposed to secondhand smoke, the CDC says.

According to the CDC study, four states have smoke-free laws covering two of three locations. Florida, Louisiana, and Nevada restrict smoking in work sites and restaurants but not in bars. North Carolina permits smoking on work sites, but not in bars or restaurants.

Alabama, Alaska, California, Connecticut, Georgia, Missouri, Oklahoma, and Virginia in at least one location permit smoking only in designated or ventilated areas.

The CDC says Delaware was the first state to adopt comprehensive smoke-free laws, on Dec. 2, 2002. It was followed by New York in 2003, Massachusetts in 2004, Washington and Rhode Island in 2005, and New Jersey, Colorado, Hawaii, and Ohio in 2006.

Comprehensive smoke-free laws were adopted in 2007 in Washington, D.C., Arizona, New Mexico, and Minnesota and in 2008 in Illinois, Maryland, and Iowa. In 2009, Utah, Nebraska, Vermont, Maine, and Montana followed suit, as did Michigan, Kansas, Wisconsin, and South Dakota in 2010.

The report states that the U.S. "made considerable progress during the past decade" in prohibiting smoking or limiting it in various areas. The CDC says 47.8% of U.S. residents are protected to some degree by comprehensive state or local smoke-free laws.

The federal government's "Healthy People 2020" goals call for all states to have laws on smoke-free indoor air in public places and work sites.